In a semiconductor manufacturing process or the like, a coating film containing a metal oxide may be employed. For example, as a method of forming a coating film containing a metal oxide, there has been known a method in which a solution of a compound containing a metal oxide is coated, a solvent is evaporated, and a baking process is performed to promote a crosslinking reaction.
In the method mentioned above, bubbles may be generated when the baking process is performed.